1. Field of the Invention
The present invention relates to a wheel spindle structure of a bicycle, more particularly to a wheel spindle structure of a bicycle having a design of high elastic force with slight elongation-contraction, which is obtained by providing a plurality of recessed grooves on the circumference and along the axial direction. In this way, the above function can be achieved and the steering capability of the bicycle is improved.
2. Brief Description of the Prior Art
Accompanying surging of oil prices, bicycle riding is booming in Taiwan, and some trends of thought such as EV, energy saving, healthy, and LOHAS are also becoming popular all over the island. The leisure activity of bicycle riding, which is suitable not only for both old and young but also for both sexes, has appropriately become a predominant activity. More and more cycling white-collar workers are apparently appeared on the city streets, while outstanding bicycle industries in Taiwan cooperate with local city or county governments actively to hold cycling free and unfettered trip or cycling challenge contest. That is to say, bicycle recreation is widespread to everywhere as if it is becoming a sport of whole people. No matter whether bicycles are used in leisure or transportation or contest, the bicycle industry considers it their own mission to unceasingly improve each bicycle part so as to make the bicycle become even better and better in its function.
It has been about 100 years since the first bicycle was developed, and the basic configuration of a typical bicycle has changed little. However, bicycle structure in the design of prior art does not keep up with the development of modern materials, as suitable materials should be adapted to suitable application. Generally, the frictional resistance, i.e., the rolling resistance produced by the rotation of wheel contacted with ground is different for different type of wheel used. The other factors affecting the magnitude of frictional resistance include such conditions as pneumatic pressure in wheel, tension of spokes, rigidity of wheel rim. The tire basically has a circular configuration, but the rotation of the tire produces vibration phenomena of cyclic bent-in and bent-out arisen from the weight of the bicycle and the rider, when the tire is contacted with ground. The vibration phenomena is more or less different depending on the difference in front fork, frame structure and materials, and resonance is even produced. To reduce the production of resonance, to buffer the front fork and the rear fork, and to improve the geometric displacement caused by the weight in movement can make the movement and steering of bicycle become smoother.
Recently, the bicycle structure has had the appeal of high elasticity, such as the utilization of aluminum alloy and carbon fiber in bicycle parts are also without exception. In dynamic condition, the parts in a bicycle structure should be well coordinated among one another. Hence, as the elasticity between associated parts should also be well coordinated, the wheel spindle having high elasticity with slight elongation-contraction is thus proposed. This wheel spindle can remarkably increase steering capability of the bicycle and reduce rolling resistance in moving according to the inference derived from Karman's principle in that the two fork openings of the front and the rear forks change their center point of circle due to such factors as elongation-contraction or structural bending arisen from the action of different forces. Hence, the fork openings at both ends might have different deformation routes, as the front and rear forks of the bicycle frame nowadays no longer have “absolute rigidity, which means non-deformable even a little under the action of force.
Seeing that combining the wheel hub and wheel body of a conventional bicycle has the shortcomings of large frictional resistance after assembly, large vibration force and overlarge rigidity strength, unsmoothness of the wheel body's rolling, or bad steering capability, the inventor of the present invention hereby proposes a wheel spindle, which is made according to Karman's principle by incorporating multiple physical effects, based on his proficient experience and knowledge in R&D and manufacturing in the relevant field such that the purpose of remarkably increasing steering capability of the bicycle and reducing rolling resistance is effectively achieved. Moreover, quick detachment of the combination of the wheel hub and frame forks is further improved so as to play more practical benefits.